Ever since the invention of the portable transistor radio, there has been an interest in portable, now known as “mobile”, electronic devices. This interest started with AM radios which people could carry and was continued with cameras and a combination cassette tape player-radio, e.g., the Walkman® radio, and now includes devices such as cameras, mobile telephones, mobile computers, tablets, MP-3 players and other devices.
As the portable/mobile devices evolved over the decades so have the demands and capabilities of such devices. With each generation of devices, the devices have been able to provide more content to their users at ever higher bandwidths and in more user friendly formats, as well as giving users the ability to create, modify and deliver content from their devices. As the convenience of these devices increased so did the power requirements for the devices as well as the technology associated with the battery for such devices. These latter generation devices contained more energy and generated greater power and consequently generated more heat. In addition to the batteries, the hardware items e.g., radios, displays and processing units, of the devices also became more powerful and likewise created additional thermal issues for such devices.
Further, as these devices have become more powerful, the trend for these devices has favored smaller, lighter and thinner, and with greater density of components inside the devices or otherwise configured so that the space available inside the casing of the device is minimized With the combination of increased power of the components inside the device and reduced internal space, thermal management of the system is a factor designers of mobile devices should take into account and has become a major consideration, and in some cases a limiting factor, to nearly all aspects of the design of high-powered, portable devices.